However the plan emerged – whether it was the US secretary of state John Kerry going off-piste at a press conference, whether it had been floated at the G20 summit last week, or whether it had been worked over in back-channel discussions for some time – it soon acquired momentum. Within 24 hours, China and Iran had backed the emerging Russia-US idea for Syria to surrender its chemical arsenal – although Iran added that this should include the chemical weapons it alleged were in rebel hands. Barack Obama, increasingly uncertain of winning congressional backing for a strike over Syria's alleged chemical weapons use, put that idea on hold and said the plan for Syria to sign the chemical weapons convention (CWC) could be a significant breakthrough. For the first time in two and a half years, everyone in the Syrian crisis – except the rebels – appears to be on the same page.

This is welcome, although that momentum was already slowing over the insistence by the US, UK and France to make a UN resolution enforceable with military action. Vladimir Putin said that a draft resolution could only work if the use of force was off the table. As the CWC process contains its own timetable and enforcement procedures, there must still be room for compromise although the meeting at the UN was postponed. The international securing of Syria's chemical weapons should be explored, however, not least because it may simultaneously stop a military strike and chart a way back to the negotiating table at Geneva. If successful, Syria's putative agreement to admit inspectors to verify and seal its chemical weapons stockpile could be accompanied by a wider ceasefire negotiated in Geneva. One agreement could lead to another.

This is emphatically not the case with a military strike. The closer Mr Obama comes to pulling the trigger, the more difficulty his advisers and spokesmen have in defining the mission. Is it an "unbelievably small, limited kind of effort" (Mr Kerry) or does "The US … not do pinpricks" (Mr Obama)? Are the strikes intended to tip the balance of power or just as a shot across the bows? The original project of arming the rebels, proposed by Hillary Clinton and David Petraeus, then secretary of state and head of the CIA, had one purpose in mind – regime change. The military option morphed, in British and French hands, into a plan to force Bashar al-Assad to the negotiating table by securing rebel gains on the ground.

Yet, as the war drags on, an Assad defeat looksincreasingly unlikely. His forces are cohesive and their lines of supply from Russia and Iran not in doubt. The rebels' forces are anything but unified. They have been Balkanised along ethnic, religious and local lines, and follow competing military strategies. Some jihadi groups are now using Syria as a base to attack Iraq.

We could swiftly reach the point, if we have not got there already, where it is not in international interests for any side to win.

If the twists and turns of the Lebanese civil war become a template for the Syrian one, peace would be a long way down the line. And if and when it came, it might not deliver a country liberated from a single dictator. Rather, it might produce a landscape dominated by lots of them, each in control of his own patch. The sooner the fighting stops, the greater the chances of stopping such Balkanisation.The diplomatic option has real advantages. The first steps are clear – Mr Assad's signature on an agreement to join the CWC – and could even be achieved almost as quickly as Mr Kerry is urging. The next steps are more difficult, but they are automatic and intrusive. Thirty days after signing, any use or stockpiling of chemical agents would be illegal and make Syria liable to emergency inspections. The practical problems of delivering this, in the midst of a civil war, should not be underestimated.

But for now, the problem and doubts over enforcement should not be allowed to obscure the ultimate goal – that if Syria signs the CWC, and it said it would, a procedure will be put in place that is more thorough and more targeted at Syria's chemical weapons stock than any military action, barring full scale invasion, could achieve.

If the CWC route takes time, so be it. Renouncing the use of force – that Mr Obama's administration is deeply divided about and struggling to define –may be the price that has to be paid.